TNF and atrial fibrillation: The TREAT-AF study, a prospective double-blind, sham-controlled, randomized clinical trial examining the effect of chronic low-level tragus stimulation (LLTS) in patients with paroxysmal AF, found that chronic, intermittent LLTS resulted in lower AF burden as assessed by noninvasive continuous electrocardiogram monitoring at baseline, 3 months, and 6 months, heart-rate variability, and tumor necrosis factor-alpha serum levels [58]; this study supported the use of LLTS as a treatment for paroxysmal AF in select patients.